iCEnhancer 2.1 on Asus 7870

[kugi_igi]

Hi, I just upgraded my rig. Actually almost 10 year worth of upgrade. I played San Andreas in the lowest possible settings. Okay enough my stories

I just started playing GTA IV 4 years after its release and I installed iCEnhancer 2.1 to have the best experience. But my average FPS is only 20. For me that's playable since I came from the crappiest of the crappiest gaming . But of course I want to improve that. the problem is even I set it to the lowest resolution which is 800x600 the FPS doesn't change (15-24fps). My real question is do get the best I can get from my PC?

here's the details:

GTA IV: Max settings except View and Detail distance at 60 reosultion @ 1920x1080

PC spceifications:

i5 3570k @ 3.4Ghz

Asus HD7870 Direct CU II

8GB RAM

I hope you I understand my post. Sorry for my bad English. Thanks!